Screen turns black, unresponsive when calling
When I make calls the screen turns black so I cannot access the UI for using the keypad and speaker, or end the call. If I press the wake button on the side of the phone, the screen turns on for maybe a quarter of a second and goes off again.
Even more frustrating, if the phoned is locked and I receive a call, the screen remains black so that I cannot answer the call. Pressing the wake button makes my ringtone stop. It isn't quite clear what happens then but I can't hear anything so I presume that the call is being declined. After this I need to reboot the phone to make it useable.
I think, but I'm not entirely certain, that this behaviour started when I upgraded to Taalojarvi.
How can I diagnose or fix the issue?
I've just tried this with the alarm function, and when the phone is locked, the screen doesn't turn on when the alarm goes off. To me, this indicates that the problem is with waking up, rather than with the phone call application.